<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>n行n列星星
    </title>
</head>
<body>
    <script>
        // 外层负责打印几行 里层负责一行有几个星星
        var rows = prompt('请您输入行数');
        var cols = prompt('请您输入列数');
        var str  ='';
        for (var i = 1; i <= rows; i++){ 

           
            for (var j = 1; j <= cols; j++){ 
            str =  str + '★';
            }
            str = str + '\n'
        }
      
        console.log(str);
    </script>
</body>
</html>
